DE3214488A1 - Self-limiting differential - Google Patents

Abstract

The invention relates to a differential with automatic differential-speed limitation, in particular for motor vehicles. In this construction, independent rotation of both driving wheels is guaranteed up to a predetermined tolerance limit (cornering). If this limit is exceeded, the differential-speed limitation automatically comes into operation, both in forward travel and in reverse. This is achieved by virtue of the fact that the differential is connected to the limiting unit via its output shafts by unequal gear wheels, the mode of operation of the said limiting unit being based essentially on the operation of self-reversing freewheels. <IMAGE>

Description

Self-limiting differential gear

The invention relates to a differential gear with automatic, frictionless Limiting the speed difference of the drive wheels, especially for motor vehicles.

The transmission should ensure problem-free driving, both on roads, as well as under the most difficult terrain conditions.

In differential gears with low internal friction 9 without lock, the full torque of the drive cannot be transmitted to the roadway, when the friction factor between a wheel and the road surface is smaller than that of the other wheel. If the friction factor of a wheel is close to zero, the entire Transferring driving force to the skidding wheel is a drive of the vehicle not possible.

Differentials with manual lock are operated by a dog clutch blocked. In this condition, engine damage cannot be ruled out if the vehicle is on a non-slip road surface. The tire wear is considerable and the result is difficult steering with an increased risk of accidents. Furthermore, Csr is larger To complain about operating effort.

In differential gears with high internal friction, spreading forces generate between disk brakes a load-dependent locking torque and all the more so j is greater the drive torque. Depending on the setting of this gear, the lock value either too small (low internal friction) or if the drive torque is high nourish the full closure. There are disadvantages here as if the hand lock is not released possible. In addition, there is constant wear of the lamellae even with "normal" Determine journey The invention is based on the object of all to exclude these deficiencies without expecting increased fuel consumption is.

This object is achieved according to the invention in that a differential gear with low internal friction via its output shafts due to unequal gears is connected to a limiting unit, the mode of operation of which is essentially is based on the function of self-reversing freewheels.

With this construction, both output shafts have an independent speed Guaranteed up to a specified tolerance limit. If this is exceeded, the speed difference limitation comes into effect automatically. Always the whole Transfer torque of the drive to the roadway. When the flow of force is reversed the positive connection is retained (motor brake). All functions are automatically effective when driving forwards and backwards.

How it works 1. The resistance of both output shafts is approximate equal, independent speed within limits desired (cornering).

The drive force is obtained from the pinion (1) via the crown wheel (2), the main shaft (3) and the spur gear (4), which are all firmly connected to each other, on the spur gear (5) transfer. From here the force is transmitted via the basket (10) and the differential bevel gears (11) evenly distributed on both output shafts (12, 13). (Fig.1) These drift in addition the boundary wheels (7,9,6,8), which the rotary movement via the claws (14,15) of the open claw clutches are transferred to the freewheeling gears (16). This one by the transmission ratios of the limiting gears (7,6), or (9,8) and the spur gears (4,5), moving faster than the pawls (17), is the connection interrupted to the main shaft (3).

(Fig.3) 2nd output shaft (12) without resistance (wheel spins) The flow of power from pinion (1) to output shaft (12) takes place as under No. 1 described. Likewise, the additional transmission of the rotary motion from the output shaft (12) for freewheeling on the crown wheel (2). Here, too, the connection to the main shaft (3) interrupted.

The output shaft (13) can no longer be taken from the differential are driven. The rotation of the freewheel teeth tends to come to a standstill.

The power flow for the output shaft (13) now takes place from the main shaft (3) to the spur gear (4) via the bolts (18) to the pawls (17). These press into the Freewheel teeth (16) and drive the limiting gears (d) via the open dog clutch (14,15) and (9), through their reduction ratio, the output shaft (13) with lower Speed than the ring gear (2) is driven. The minimum speed is thus, at given speed of the ring gear, limited.

Due to the well-known mode of action of the differential gear, the maximum speed is the output shaft (12) is also limited.

Thus, the maximum speed difference between the two output shafts is due to the Gear ratios specified in the "self-limiting differential gear".

3. Output shaft (13) without resistance.

The function here is analogous to No. 2.

4. Reversal (change of direction of rotation).

Special components of this invention are the automatic reversing Freewheels, through which a problem-free change in the direction of rotation of the "self-limiting Differential gear "is possible Description of the pre-run in Fig. 2, 3 and 4.

The pawls (17) are connected to the toothed segments (19) via the bolts (18) connected, which engage in the synchronous toothing (20) of the escapement ring (21). This is easily pushed against the escapement bearing (24) by its balls (23) under spring pressure (22) braked. C, the escapement bearing is firmly connected to the main bearing (25), which is fastened with its foot (26) on the gear housing (27).

If the freewheel carrier (spur gear (4)) rotates, the pawls (17) by the braking action of the locking ring (21) moves in the same direction of rotation until it have reached their target position (Fig.3). Lose at increasing speeds the balls (23) their braking effect by centrifugal force. Now the pawls (17) even through centrifugal forces and hydraulic forces (gear oil) on the synchronous toothing (20), held in debit position.

When reversing in a different direction of rotation, it must be prevented that the faster rotating freewheel teeth (16) with the slower moving The pawls (17) are jammed.

The open claw coupling and its inner claws are provided for this purpose (15) form a unit with the freewheel gearing (16) and their outer claws (14) are firmly connected to the limiting wheel (8). The claws (14,15) can be approx. Turn 600 against each other (Fig.3).

Thus, when the direction of rotation is changed, the freewheel carrier (spur gear (4)) the freewheel teeth (16) always run ahead so that the pawls are free can solve to pivot into their new target position.

Both freewheels and dog clutches form the "limiting unit".

Claims (2)

Claims 1. Self-limiting differential gear as drive wheel compensation or transfer case for wheel or caterpillar driven vehicles as well as industrial & machines and systems, characterized in that the output shafts of a differential gear be connected to a limiting unit by gears. 2. Self-limiting differential gear according to claim 1, characterized characterized in that the limiting unit is equipped with self-reversing freewheels that automatically adapt to any change in the direction of rotation.